Inserter apparatus

ABSTRACT

Apparatus for inserting a content pack into an envelope, the apparatus comprising: a gripping mechanism; means for operating the gripping mechanism to hold an envelope; means for opening a throat of the envelope; means for moving the content pack in a direction toward and into the throat of the envelope; means for accelerating the envelope in the direction of movement of the content pack while the gripping mechanism is operational; and means for releasing the gripping mechanism at a predetermined time, to release the envelope, the predetermined time being while the content pack is at least partially inserted into the envelope, and being predetermined in dependence upon parameters comprising at least the content pack depth and the envelope depth.

BACKGROUND OF THE INVENTION

The present invention relates to an inserter apparatus particularly fora paper handling machine used for inserting documents and inserts intoenvelopes, and a method of controlling such apparatus.

In the paper handling industry envelopes are required to be filled withcontents which may include documents such as personally printed letters,standard pre-printed letters, leaflets, brochures, and other insertssuch as credit cards. There are many steps required to fill an envelopewith such contents. Firstly both the envelope and the contents (suitablyfolded if necessary) must be transported from storage hoppers of therespective items along paths which converge at an inserter station. Thenthe envelope flap must be folded out, the envelope pouch opened enoughto give clearance to insert the contents, and then the contents must bepushed into the envelope. The flap of the filled envelope must be closedand sealed, and finally the envelope must be transported away from theinserter station. It is desirable to complete this process at very highspeed: up to 3,000 envelopes per hour can be filled in the highest speedmachines available today.

Precise tolerances must be observed to ensure that the machine runssmoothly particularly at such high speed so that loss of production iskept to a minimum. If the contents are incorrectly aligned with theopening of the envelope then they will not fit into the envelope pouchand the envelope and/or the contents will be damaged, and the productionline will need to be halted to clear debris from the inserter station.Equally, if the contents are not pushed completely into the envelopethen the flap will not fold back, or seal, and production will be lostand delayed.

One way of ensuring accuracy of insertion is to bring envelopes andcontents together to an inserter station and push the contents into theenvelope while it is stationary, then to move the envelope out of theinserter station for further processing. Although this makes it easierto ensure accuracy, it is a relatively slow method.

A faster method is to begin the insertion process while the envelope isstationary and release it as the insert is moving into the envelope soas to use the momentum of the insert to drive the envelope out of theinserter station. This speeds up the production line but requires veryaccurate synchronisation to ensure that the envelope is released atprecisely the right moment. If the timing is wrong then either theinsert does not fit completely into the envelope, or it hits the bottomof the envelope while the envelope is being held, and the impact canthen damage the envelope and/or the insert. In addition a lightweightinsert may have insufficient momentum to overcome the inertia of theenvelope to drive it fully out of the inserter station.

One attempt to overcome some of these problems involves driving theenvelope at the same time as releasing it, for example the envelopeholding mechanism may be released using solenoids, which may also beused to drive pressure rollers to apply pressure to connect the envelopewith constantly running drive rollers. However positional control andcoordination of such a system is difficult and the envelope may moveearly, ahead of the insert, or late such that the envelope is driven bythe insert instead of the rollers.

One known system for synchronising an envelope inserter is described inU.S. Pat. No. 6,418,357. This uses positional information, provided by asensor, to generate motion profiles to synchronise an envelope drivewith an insert drive. U.S. Pat. No. 6,813,870 teaches a method ofspeeding the insert stage by feeding inserts and envelopes from the samedirection. This avoids the loss of speed necessary when they aretransported from different directions, which requires that one or bothchange direction at the inserter station. U.S. Pat. No. 7,051,496describes a method of feeding envelopes to an inserter station andincreases the speed at which this is done by driving the envelopes intocontinuously moving gripping members at a faster speed than the grippingmembers are moving. This ensures that the envelopes are fully engagedwith the gripping members so that they are accurately positioned in theinserter station, whilst speeding up their transport into it.

It is also desirable that the inserter can accommodate a variety ofsizes, shapes, and weights of envelopes and inserts. It will beappreciated that many sizes and shapes of envelopes are available, andinserts can vary in size and in thickness considerably, depending uponthe nature and number of the contents. It is a challenge to ensure thatthe insert and the envelope move in unison and engage togetheraccurately at high speed regardless of size, shape, strength and weight.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is providedapparatus for inserting a content pack into an envelope, the apparatuscomprising: a gripping mechanism; means for operating the grippingmechanism to hold an envelope; means for opening a throat of theenvelope; means for moving the content pack in a direction toward andinto the throat of the envelope; means for accelerating the envelope inthe direction of movement of the content pack while the grippingmechanism is operational; and means for releasing the gripping mechanismat a predetermined time, to release the envelope, the predetermined timebeing while the content pack is at least partially inserted into theenvelope, and being predetermined in dependence upon parameterscomprising at least the content pack depth and the envelope depth.

Preferably the predetermined time at which the envelope grippingmechanism is released corresponds to the time at which the content packis substantially fully inserted in the envelope.

The time may be predetermined also in dependence upon the thickness ofthe content pack.

Stepper motors may be used to drive the content moving means and/or thegripping mechanism and/or the envelope acceleration means, and suchstepper motors may be synchronised.

The parameters from which the predetermined time is calculated may bestored as job-specific data or may be entered by an operator, or may bemeasured by one or more sensors.

According to one embodiment the gripping mechanism is arranged to gripthe envelope flap and the parameters further comprise the flap depth.

BRIEF DESCRIPTION OF DRAWINGS

For a better understanding of the present invention, and to show how thesame may be carried into effect, reference will now be made to theaccompanying drawings, in which:

FIG. 1 is a simplified schematic side view of the inserter apparatusaccording to the present invention;

FIG. 2 is a more detailed schematic side view of the inserter apparatusaccording to the invention;

FIGS. 3 a to 3 e illustrate the operation of the inserter apparatus ofFIGS. 1 and 2.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

In FIG. 1 a content pack 1 is shown, on a content conveyor platform 2,moving in the direction of arrow 3 towards an envelope 4. The envelope 4rests on an insertion platform 5 with its flap 8 open, and is held inposition at the inserter station, by a gripping mechanism which gripsthe envelope flap 8. The gripping mechanism comprises a grip bearing 6and grip rollers 7 (one of which can be seen in the figure).

In FIG. 2 more detail is shown. The content pack 1 is driven along thecontent conveyor platform 2, by a kicker drive pawl 9 attached to akicker pawl belt 10. A second kicker drive pawl 19 is positioned at adiametrically opposed position on the belt 10, so that two content packscan be driven with one rotation of the belt. Of course any reasonablenumber of pawls may be attached to the belt to drive successive contentpacks. The kicker pawl belt 10 is driven by a kicker drive stepper motor11, which drives a wheel 12 by a kicker drive belt 13. The grippingmechanism holds the envelope 4 by its open flap 8 between gripperrollers 7 and gripper bearing 6, and moves it into position in theinserter station so that its flap side faces toward the approachingcontent pack 1. A second independent stepper motor 17 is used to controlthe envelope gripper rollers 7 via an envelope gripper belt 18.

When the envelope is correctly positioned, the front and back faces ofthe envelope are separated by a finger arm comprising a finger 15 hingedat 16 to a lever 14, which is driven in a reciprocating motion so thatthe finger 15 is driven into the open flap side, i.e. the throat, of theenvelope, between the front and back faces. The finger 15 then movesinto a more vertical orientation to separate the faces and open theenvelope. The content pack 1 is then driven by pawl 9 into the envelope4 between the faces and the finger 15 is lowered. The direction ofmotion of the finger 15 is then reversed. As the content pack 1 isdriven into the envelope, the gripper drive stepper motor 17 is startedto move the flap gripper rollers 7 anticlockwise to drive the flap 8,and thus the envelope 4, out of the gripping mechanism, and acceleratethe envelope in a downstream direction on the insertion platform 5.

This is illustrated more clearly in FIGS. 3 a to 3 e. In FIG. 3 a theenvelope 4 is positioned in its correct position in the inserter stationby the flap gripper stepper motor 17 and the flap 8 is held between theflap gripper rollers 7 and the gripper bearing 6, using a holdingcurrent applied to the stepper motor 17. At the same time the kickerpawl 9 starts to move and picks up and pushes the content pack 1 in thedirection of arrow 3 towards the envelope 4.

The content pack 1 moves toward the envelope 4 as the finger 15 movesinto the throat of the envelope 4 to open it, in advance of the contentpack 1 arriving. The content pack 1 then moves into the envelope 4 asshown in FIG. 3 b. The flap gripper stepper motor 17 starts to drive theflap 8 and thus the envelope 4 as shown in FIG. 3 c. The exact timingand speed of operation of the flap gripper stepper motor 17 depends uponcalculations made using one or more parameters such as the envelope flapdepth, the envelope depth, the content pack depth and the content packthickness. At the same time the friction between the content pack 1 andthe envelope 4 may also cause movement of the envelope.

The operation timing is controlled so that when the content pack 1 isfully inserted into the envelope 4, as shown in FIG. 3 d, the envelope 4will have been accelerated so that it is moving almost as fast or at thesame speed as is the content pack 1, and the kicker drive pawls 9, 19.At this moment, the flap gripper releases the flap 8 because the end ofthe flap slides out from the grip of the gripping rollers 7 and the gripbearing 6.

In FIG. 3 e the envelope flap 8 is shown fully released and the envelope4 is driven by the momentum of the content pack 1 inside it and by thepawl 9.

1. Apparatus for inserting a content pack into an envelope, theapparatus comprising: a gripping mechanism; means for operating thegripping mechanism to hold an envelope; means for opening a throat ofthe envelope; means for moving the content pack in a direction towardand into the throat of the envelope; means for accelerating the envelopein the direction of movement of the content pack while the grippingmechanism is operational; and means for releasing the gripping mechanismat a predetermined time, to release the envelope, the predetermined timebeing while the content pack is at least partially inserted into theenvelope, and being predetermined in dependence upon parameterscomprising at least the content pack depth and the envelope depth. 2.Apparatus according to claim 1 wherein the predetermined time at whichthe envelope gripping mechanism is released corresponds to the time atwhich the content pack is substantially fully inserted in the envelope.3. Apparatus according to claim 1 wherein the content pack moving meanscomprises a stepper motor driving a pawl to push the content pack intothe envelope.
 4. Apparatus according to claim 1 wherein the time ispredetermined also in dependence upon the parameter of the thickness ofthe content pack.
 5. Apparatus according to claim 1 wherein the grippingmechanism and the envelope acceleration means are driven by a steppermotor.
 6. Apparatus according to claim 1 wherein at least one of theparameters is stored as job-specific data in apparatus control software.7. Apparatus according to claim 1 wherein at least one of the parametersis entered by an operator during job set-up.
 8. Apparatus according toclaim 1 wherein at least one of the parameters is measured by a sensorupstream of the inserter.
 9. Apparatus according to claim 1 wherein thegripping mechanism is arranged to grip the envelope flap.
 10. Apparatusaccording to claim 9 wherein the parameters further comprise theenvelope flap depth.
 11. Apparatus according to claim 1 wherein theaccelerating means is operable via the gripping mechanism.
 12. Apparatusaccording to claim 1 wherein the accelerating means is driven by a firststepper motor.
 13. Apparatus according to claim 12 wherein the contentpack is driven into the envelope by a pusher pawl driven by a secondstepper motor.
 14. Apparatus according to claim 13 wherein the firststepper motor and the second stepper motor are synchronised. 15.Apparatus according to claim 1 wherein the acceleration of the envelopecontinues until the gripping mechanism is released.